Which Filters to Buy for Your HVAC System

HVAC filters play an important role in maintaining indoor air quality and protecting your HVAC system. The filters capture contaminants and particles in your air and prevent them from collecting inside the air handler and duct system. In return, this also provides cleaner air for your home. If you do not replace your filters on a regular basis, we highly suggest starting now! Not only will it help extend the life of your HVAC system, but it also can help protect your family’s health. 

Primary Functions of HVAC Filters

HVAC filters help trap airborne particles and contaminants so they do not circulate through out your home. Filters trap particles such as pollen, pet dander, mold spores, and even viruses and bacteria in some cases. This helps improve your indoor air quality and helps promote a clean and healthy living space. Filters also act as a layer of protection for HVAC system components such as the blower motor, coils, heat exchanger, and other fragile parts of the system. Reducing the number of particles that come in contact with these components can help extend the life of your system and help it run efficiently. 

What Kind of Filters Should I Buy?

The first step in determining which filters to buy is to look at how your HVAC system was set up and determine where your current filters are located. Some homes will have an air filter at the air handler, and others will have filters at each of the return air grills. If you have a filter at the air handler, return air grill filters are not necessary, so it is common for newer homes to just have one filter on the air handler. If you have multiple HVAC systems, you will have multiple air handlers, so make sure to check each of the filters. 

There are a variety of filters on the market, each with different quality levels and capabilities. Some filters that are attached to the air handling unit are up to 4 inches thick. These are usually brand specific and will need to be sourced according to the manufacturer of the filter or Stan’s can help. When replacing this filter, it is usually best to purchase a replacement with the same specs. The filters on return air grills are usually 1 inch thick and need to be replaced more frequently. These are the standard filters you see sold in many grocery and home improvement stores. Regardless of what type of filters you have, make sure to look at your current filters to find the dimensions you will need before you start shopping.

When shopping for new filters, you will find many different options available, especially when it comes to standard 1-inch filters. Some will be marketed towards pet owners or those that suffer from allergies, but the most important thing to look at is the MERV rating. This gives you an idea of what type of particles that filter is capable of capturing. The most affordable options will probably be made of lower quality materials and will not be able to capture as many types of contaminants as a higher rated filter. 

What is a good MERV rating?

Air filters all have a Minimum Efficiency Reporting Value, or MERV rating. This tells us what kinds of particles the filter can remove from your air. This is important to know because anything the filter cannot capture will be left to circulate throughout your home or build up in your ducts. You will see filters ranging from MERV 1 to MERV 16. The lowest MERV rating you should purchase is 6. This type of filter can capture lint, dust, and pollen. The next step up would be a MERV 8 filter. This filter can capture everything a MERV 6 and below can, in addition to mold spores and dust mites. Once you go above a MERV 8, with a 1-inch filter, the filter will generally be too restrictive for your system to properly operate. When using a filter above MERV 8, the filter should be thicker to provide more surface area. These filters are two to four inches thick and the system has to be designed to accommodate the larger filter. Once you reach a MERV 11 rating, the filter will also capture pet dander and smoke. If you have a pet, you should look for a filter with at least a MERV 11 rating to help minimize the pet dander circulating throughout your home. On the higher end of the scale, you will find a MERV 13 filter which can filter out bacteria and viruses as well but may restrict air flow. At Stan’s we install MERV 11 filters, which is what we recommend for most households. Once you go higher than MERV 11, the HVAC system’s total static air pressure can be compromised. If you are interested in a filter with a higher MERV rating, you would need to have your ductwork enlarged to handle the greater airflow needed for such a restrictive filter. 

If you are shopping for filters for your return air vents, you may also come across electrostatic filters, often referred to as reusable filters which can be used in place of standard 1-inch filters. As the name implies, these are filters that you are able to wash and reuse. They use static electricity along with mesh to remove particles from the air in your home. While these are convenient and eco-friendly, they tend to be more restrictive to air flow. Over time, the small pores within the filters become clogged to the point where it becomes difficult to effectively clean them. This leads to even more restriction over time. They also have to be washed and dried at least once per month. 

How Often to Change Filters

Clean filters help your system run efficiently and can reduce the amount of energy needed to keep your home comfortable, so it is important to replace your filters on a regular basis. When filters are full of dust and debris, air flow is restricted, which puts more strain on your system. The thick filters, 4-inches and up, can usually last about 6 months to 1 year, and 1-inch filters can last about 1 to 3 months. If you suffer from allergies, have pets in your home, or live somewhere with a lot of dust, you may have to replace the filters even more frequently. We suggest checking your filters on a monthly basis to determine what is best for your home. 

Replacing your air filters is an excellent way to protect your HVAC system and improve the air quality for your family. Just make sure you buy the correct size filters for your home! The quickest way to determine what size you need is to look at the dimensions listed on the sides of your current filters. If you are interested in having your filters changed for you or have questions about the best filters for your home, contact Stan’s today!

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